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Week 3: Ductwork Foundations
Master the fundamentals of ductwork design, installation, and maintenance in this comprehensive bootcamp module.
Week 3 Learning Objectives
This week marks a critical milestone in your HVAC journey. By the end of these sessions, you'll have the foundational knowledge and hands-on skills needed to tackle ductwork projects with confidence and precision.
01
Master Airflow Fundamentals
Understand CFM calculations, static pressure relationships, and velocity principles that drive effective ductwork design.
02
Identify Duct Materials
Compare flex duct, sheet metal, and duct board applications to select the right material for each installation scenario.
03
Apply Design Principles
Calculate proper duct sizing, plan efficient layouts, and avoid common design pitfalls that compromise system performance.
04
Execute Professional Installation
Demonstrate proper sealing techniques, insulation standards, and quality control measures that meet Daycool's high standards.
Airflow Principles: The Science Behind Comfort
Understanding airflow is like learning the language of HVAC systems. Every duct, fitting, and connection affects how air moves through a building, directly impacting comfort and energy efficiency.
CFM: Cubic Feet per Minute
CFM measures volume of air movement. A typical residential system moves 400 CFM per ton of cooling capacity. Too little airflow reduces efficiency and comfort; too much wastes energy and creates noise.
Static Pressure
This is the resistance air encounters moving through the system. Think of it like water pressure in pipes – restrictions create back-pressure that forces your equipment to work harder.
Air Velocity
Speed of air movement through ducts. Optimal velocity balances efficiency with noise levels. Supply ducts typically run 600-900 feet per minute, while return ducts operate at lower velocities.

Pro Tip: Always measure static pressure at multiple points during commissioning. High readings indicate restrictions that need immediate attention.
Why Ductwork Matters
Quality ductwork is the circulatory system of HVAC. Poor ductwork can waste 20-40% of energy, create hot and cold spots, and lead to expensive callbacks. At Daycool, we build systems that last.
Energy Efficiency
Properly sealed and insulated ductwork prevents conditioned air from escaping into unconditioned spaces, reducing energy waste and lowering utility bills for homeowners.
Comfort Control
Well-designed duct systems deliver consistent temperatures throughout the home, eliminating hot and cold spots that frustrate customers.
Indoor Air Quality
Sealed ductwork prevents contaminated air from crawl spaces and attics from mixing with clean indoor air, protecting occupant health.
System Longevity
Proper ductwork reduces strain on HVAC equipment, extending lifespan and reducing maintenance costs over time.
Ductwork Materials: Choosing the Right Tool
Each ductwork material has specific applications, advantages, and installation requirements. Understanding when to use each type is essential for professional results.
Flexible Ductwork
Most common in residential applications. Easy to install around obstacles, cost-effective, but requires careful handling to prevent kinking. Maximum length runs should not exceed 25 feet. Always support every 4 feet and avoid sharp bends.
Sheet Metal Ducts
The gold standard for commercial and high-end residential work. Galvanized steel offers durability and smooth airflow. Rectangular and round options available. Requires skilled fabrication but provides superior performance and longevity.
Duct Board
Fiberglass board with integrated insulation and vapor barrier. Excellent for straight runs in conditioned spaces. Lighter than metal, provides good insulation value, but less durable than metal options. Popular for trunk line applications.
Duct Design Basics
Proper duct design is both art and science. It requires understanding building layout, equipment capacity, and airflow principles to create systems that perform efficiently and quietly.
Sizing Calculations
Start with Manual D calculations to determine proper duct sizes. Each room requires specific CFM based on load calculations. Undersized ducts create excessive velocity and noise; oversized ducts waste materials and reduce air throw.
Layout Planning
Design shortest, straightest paths possible. Every elbow and fitting adds resistance. Plan for proper return air pathways – inadequate returns cause system imbalance and reduce efficiency.
Zone Considerations
Group areas with similar heating and cooling needs. Consider sun exposure, occupancy patterns, and architectural features when planning duct runs and outlet locations.

Critical Rule: Never size ducts based on register size alone. Always calculate required CFM first, then select appropriate duct dimensions.
Essential Ductwork Tools
Professional ductwork installation requires specialized tools. Having the right equipment ensures quality results, improves efficiency, and demonstrates professionalism to customers.
Measuring & Marking
  • 25-foot tape measure with standout
  • Permanent markers and pencils
  • Speed square for accurate cuts
  • Level for proper slope verification
Cutting Tools
  • Duct knife for flex duct cutting
  • Aviation snips (left, right, straight)
  • Hole saw set for register openings
  • Reciprocating saw for access holes
Fastening & Sealing
  • Cordless drill with metal bits
  • Self-tapping screws (#8 x 1/2")
  • Mastic sealant and brush
  • Aluminum foil tape (UL 181A-P)
Safety Equipment
  • Safety glasses and dust masks
  • Work gloves (cut-resistant)
  • Knee pads for crawl space work
  • Headlamp for dark spaces
Insulation & Sealing Standards
Proper insulation and sealing separate professional installations from amateur work. These standards ensure energy efficiency, prevent condensation issues, and meet code requirements.
Insulation Requirements
All ductwork in unconditioned spaces requires minimum R-6 insulation. Use R-8 in extreme climates or when specified. Vapor barriers must face away from conditioned air to prevent moisture problems.
  • Attic installations: R-8 recommended
  • Crawl space applications: R-6 minimum
  • Basement locations: R-4 acceptable
  • Exterior wall chases: R-8 required
Sealing Standards
All joints and connections must be sealed with UL 181-approved materials. Duct tape is never acceptable for permanent installations. Mastic provides the most durable seal for accessible joints.
  • Mastic: Best for accessible connections
  • Foil tape: UL 181A-P for metal ducts
  • Mesh tape: UL 181B-FX for flex duct
  • Aeroseal: For existing, inaccessible ducts
Common Ductwork Mistakes
Learning from common mistakes helps you develop professional instincts and avoid costly callbacks. These issues plague many installations but are completely preventable with proper technique.
Crushed Flex Duct
Inadequate support causes flex duct to sag and restrict airflow. Support every 4 feet maximum, ensure gentle curves with large radius bends, and never compress inner liner during installation.
Air Leakage
Unsealed joints waste 20-40% of conditioned air. Seal all connections with appropriate materials, inspect work with smoke pencils, and perform blower door testing when possible.
Improper Sizing
Guessing duct sizes creates performance problems. Always calculate CFM requirements, use Manual D procedures, and verify velocities stay within acceptable ranges for noise control.
Poor Return Air Design
Inadequate return paths cause system imbalance and reduced efficiency. Size return ducts for 25% lower velocity than supply ducts and ensure adequate return air pathways from all conditioned spaces.
Daycool Duct Standards
At Daycool, we exceed industry standards because our reputation depends on long-term performance. These standards have been developed through 17 years of field experience and reflect best practices that minimize callbacks and maximize customer satisfaction.
Quality First
Every joint sealed, every support properly spaced, every installation tested and documented. We take pride in work that lasts decades, not just years.
Performance Standards
Systems must meet or exceed design specifications. We verify airflow, test for leakage, and ensure proper operation before considering any job complete.
Customer Focus
Clean work areas, protect customer property, and explain system operation. Professional appearance and courteous service build lasting relationships.

Daycool Promise: If it doesn't meet our standards, it doesn't leave our hands. Period.
Lab Assignment: Build & Seal Practice
Hands-on experience reinforces classroom learning. This lab exercise simulates real-world conditions you'll encounter in the field, allowing you to practice techniques in a controlled environment.
Assignment Overview
Working in teams of two, you'll construct a 10-foot section of flex duct with two 90-degree turns, properly support the assembly, and seal all connections to professional standards.
Required Materials
  • 10 feet of 8-inch flex duct
  • Two 90-degree metal elbows
  • Duct hangers and support straps
  • Mastic sealant and brush
  • UL 181B-FX mesh tape
Success Criteria
  • No visible air leaks during smoke test
  • Proper support every 4 feet
  • Smooth, unrestricted airflow
  • Professional appearance

Safety First: Wear safety glasses when cutting metal and gloves when handling sharp edges. Work gloves prevent cuts from duct materials.

Pro Technique: Stretch flex duct to full extension before making connections. This ensures maximum airflow and prevents restriction.
Week 3 Knowledge Check
Test your understanding of ductwork fundamentals with this comprehensive quiz. These questions reflect real-world scenarios you'll encounter as a Daycool technician.
01
Airflow Calculations
A 3-ton residential unit requires how many CFM? What static pressure reading indicates excessive system resistance?
02
Material Selection
When would you choose sheet metal over flex duct? What are the maximum length limitations for flex duct runs?
03
Installation Standards
What sealing materials are approved for permanent duct connections? How often must flex duct be supported?
04
Problem Solving
A customer complains about hot and cold spots. What ductwork issues could cause this problem?

Passing Score: 80% or higher required to advance. Retake opportunities available with additional study time.
Week 3 Wrap-Up
Congratulations on completing Ductwork Foundations! You've mastered critical skills that form the backbone of professional HVAC installation. These fundamentals will serve you throughout your career at Daycool.
100%
Core Concepts
Airflow principles, material properties, and design fundamentals
85%
Hands-On Skills
Installation techniques, sealing methods, and quality standards
95%
Daycool Standards
Company expectations, customer service, and professional practices
Your commitment to excellence in these foundational areas will distinguish you as a professional technician. Quality ductwork installation prevents callbacks, ensures customer satisfaction, and builds the reputation that Daycool has maintained since 2007.
Coming Next Week
Week 4: Installation Basics
Next week, we'll build on your ductwork knowledge as we dive into complete system installation. You'll learn equipment placement, refrigerant line installation, electrical connections, and startup procedures that bring HVAC systems to life.
Equipment Placement
Proper positioning for efficiency, service access, and code compliance
Refrigerant Lines
Line sizing, insulation, and leak-free connection techniques
Electrical Connections
Safe wiring practices, control circuits, and troubleshooting basics
System Startup
Commissioning procedures, performance testing, and customer handoff
Stay Cool with Daycool - Your Journey to HVAC Excellence Continues!